diff --git a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
index d5576ae..6288323 100644
--- a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -552,7 +552,7 @@ protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $res
       // Add an index for the 'published' entity key.
       if (is_subclass_of($entity_type->getClass(), EntityPublishedInterface::class)) {
         $published_key = $entity_type->getKey('published');
-        if (!$storage_definitions[$published_key]->hasCustomStorage()) {
+        if ($published_key && !$storage_definitions[$published_key]->hasCustomStorage()) {
           $published_field_table = $table_mapping->getFieldTableName($published_key);
           $id_key = $entity_type->getKey('id');
           if ($bundle_key = $entity_type->getKey('bundle')) {